Average hotels or restaurants generally adopt a central food preparation system of which the kitchen has much higher service frequency and a larger quantity of exhausted oily smoke than those of an average family kitchen.
Conventionally, the oily smoke yielded from a central food preparation system is conducted by simple air conduits and exhausted to the outdoors. The work to install such a smoke exhausting apparatus is usually troublesome and time-consuming. More important, the conventional air conduit merely guides oily smoke to the outdoors atmosphere. This leads to the pollution of the building appearances and makes buildings badly ugly in the long run. Moreover, directly to release oily smoke will bring severe contamination to the nearby environment. Nowadays, the sense of environment protection is rapidly promoted. The situation of contamination has got to be improved.